The objectives of the work in our laboratory are to purify some antibiotic-sensitive enzymatic reactions in bacterial cell wall synthesis and to study in detail the mechanism of inhibition of these enzymes by the relevant antibiotics. There are a number of enzymes and antibiotics which are of interest in this connection. Peptidoglycan transpeptidase catalyzes the terminal cross-linking of peptidoglycan strands. This reaction is inhibited by penicillin and cephalosporins. It is one of the penicillin binding components of bacteria. The physiological role and various aspects of the biochemistry of the penicillin binding components of several bacterial species are also under study.